An investigation was made of the influence of an electric field on the transmission of a multilayered structure consisting of CdS and glass films. The same shift of the fundamental absorption edge was observed with the application of an electric field of 10–50 V to the sample as for a single crystal with a high applied voltage of about 1000 V. We also obtained a large‐modulation degree at longer wavelengths of 0.55–1.4 &mgr; than at the wavelength of the fundamental absorption edge of CdS and obtained light‐intensity modulation of the He&sngbnd;Ne laser at 6328 Å.